The invention relates to hydraulically activated three-way-valves, especially for gas-fired instantaneous hot water supply systems.
Instantaneous gas-boilers are known which can switch between domestic hot water production and hydronic room heating. In both cases water acts as a heat carrier. This water passes either through the radiators or through a heat exchanger which transfers heat from a water circuit to domestic hot water. In these cases the generation of domestic hot water has preference to the room-heating. The switching between the two circuits is performed by a three-way-valve. This three-way-valve can be activated by reversing the rotation of the circulator pump. The disadvantage is that a first valve element has to be connected to the second valve element by a traverse which can lead to a blockage or to leaking.
The invention prevents these disadvantages. The invention refers to three-way-valves which are activated hydraulically. The valves according to the invention comprise membranes, which separate a fluid chamber from the water circuit. The membranes for instance can be connected to two pressure sensors which are located close to the periphery of a reversible pump impeller or they can be connected to both sides of an orifice within the hot water circuit. The three-way-valves are also suitable for swimming pools. An object of the invention is also the coordination with the elements of an instantaneous gas heater or of a swimming pool-installation.